Spec compliant video constraints for getUserMedia behind flag.

content/renderer/media/video_track_adapter.cc

Index: content/renderer/media/video_track_adapter.cc
diff --git a/content/renderer/media/video_track_adapter.cc b/content/renderer/media/video_track_adapter.cc
index 266adf2a4f57928c534a3d8044939e2dbab649f8..b5a742bd84d3e56f168fe7ee2888a696dce201ba 100644
--- a/content/renderer/media/video_track_adapter.cc
+++ b/content/renderer/media/video_track_adapter.cc
@@ -324,6 +324,13 @@ bool VideoTrackAdapter::VideoFrameResolutionAdapter::MaybeDropFrame(
   return true;
 }
 
+VideoTrackAdapterSettings::VideoTrackAdapterSettings()
+    : VideoTrackAdapterSettings(std::numeric_limits<int>::max(),
+                                std::numeric_limits<int>::max(),
+                                0.0,
+                                std::numeric_limits<double>::max(),
+                                0.0) {}
+
 VideoTrackAdapterSettings::VideoTrackAdapterSettings(int max_width,
                                                      int max_height,
                                                      double min_aspect_ratio,